Saving Grace – Part Six

“Unreliable and unjustifiable, its cars had become a laughing stock, its management a comedy and its accounts a tragedy. Only when it began to take itself very seriously indeed, to cultivate the quality it had previously scorned did things change…” (LJK Setright – Car 1986)

It has been retrospectively stated that the Egan-led quality drive was more illusory than real, which is perhaps a little unfair to the huge effort from all concerned. There was however, in Egan parlance, perhaps a little more sizzle than steak to it. Nevertheless, the reforms had a basis in fact and if the JD Power statistics were any guide, it’s evident that Jaguar made significant strides in this area.

In 1983, BMW’s Eberhard von Kuenheim toured the Browns Lane facility. What he made of it is undocumented, but he must have been, to say the least, given to a measure of incredulity. Nevertheless by then, Jaguar had largely got to grips with building Series III to an acceptable standard. However, that standard remained discernibly lower than that of its Munich rival and at the time, potential suitor.

The XJ bodyshell, while now more accurately put together, remained a patchwork requiring a high degree of hand-finishing, its interior an alluring combination of tastefully matched, finely crafted natural materials and cheap-feeling injection mouldings, while its final assembly remained locked in the past.

A major upswing in durability terms occurred once Jaguar embarked upon a full-time on-site proving regime, building a dedicated base in Phoenix, Arizona. Regular forays to the Nardo test-track in Southern Italy and to the Middle East, Australia and Canada led to significant improvements for the customer.

But what hadn’t changed was the fact that the cars remained sensitive to neglect or careless ownership and were not as robust as they needed to be, especially once they reached their second or third owners. But Series III (and the XJ-S) were late-’60s designs with inbuilt design limitations and there was probably a limit to what could be achieved without significant and highly expensive alterations.

Ironically, the model which formed the bulk of global Series III sales was perhaps the most mechanically fragile. The 4.2 litre version of the long-lived XK in-line six had been something of a botch-job by Jaguar standards. Necessitating an element of jiggery-pokery in order to gain the additional bore widths, the engine became fundamentally compromised from a thermal standpoint.

4.2 XK (left) and 5.3 V12 (c) Jaguar Cars

Reviewing the technicalities of Jaguar’s revived mid-range engine in 1979, Car magazine’s LJK Setright noted the much-needed alterations had resulted in a torque curve of remarkable linearity, with maximum torque being developed at a mere 1500 rpm, which meant the driver never really needed to explore the upper reaches of the rev range, where the 4.2 tended to lose its composure and get decidedly hot under the collar.

Despite its physical size and vast weight, (as heavy as the larger V12), the 4.2 gained a reputation as a fragile engine and was never much regarded within Browns Lane. It’s certainly no accident that the factory never raced it.

Yet it outsold the more complex but superior V12 unit by a huge margin, despite offering broadly similar fuel economy. Yes the twelve cost more – to buy, to service and most likely in depreciation (always a Jaguar bugbear), but it offered something utterly unique – an uncanny smoothness and silence of operation, which as Jim Randle observed to this author, was as close to the characteristics of an electric motor as an internal combustion engine could reasonably be contrived.

But if the V12 cost more, the 4.2 was in turn worth far less. The irony of course being that while the V12 was designed expressly with the US market in mind, it was not sold there (in the XJ saloon at least) from 1983-onwards.

Viewed with hindsight, Jaguar made a fundamental error in prioritising the twelve over a smaller capacity unit. The contemporary thinking was that a V8 could be built on the same architecture, but for a variety of reasons it wasn’t possible (at the time at least) to create a unit which met Jaguar standards of smoothness.

(c) Car Magazine

Unfortunately, what doesn’t appear to have been explored was a similarly derived V6 unit. While an experimental 2.7 litre slant six was created off the V12 block, a 60° V6 of broadly similar capacity would have offered a more compact package, the inherent mechanical balance implicit with a 60° inclined angle, and the ability to build it on the same underutilised and expensive transfer line as the twelve.

The primary drawback would of course have been a lack of swept volume, but as an entry level unit, it could have offered many advantages and with the benefit of forced induction, could have given Jaguar the outputs they required. Certainly, a Series III with a lightweight, more fuel efficient (and sweet-running) engine not only seems a highly alluring prospect, but something of a missed opportunity. Furthermore, such a power unit could have proven highly advantageous to BL, being precisely the capacity required for the upper reaches of the Rover SD1 range, for example, rather than the larger than ideal Buick-derived 3.5 litre V8.

By the late ’70s, the necessity for a large-capacity diesel powerplant became apparent within BL. Upon Spen King’s suggestion, a diesel unit based on the block of the existing Rover V8 was developed in conjunction with Perkins. Primarily intended for Land Rover, but also for SD1, there were suggestions at the time that Jaguar could also be a recipient of what became known as the Iceberg programme. However, it fell victim to BL’s cash crisis.

A powertrain project which came a good deal closer to fruition was XJ59 – a Jaguar programme which saw the adoption of a VM Motori turbodiesel which was fitted to a number of SIII development cars around 1981/82. This unit, an in-line six of 3.6 litres, developed 150 bhp at 4200 rpm and 288 lbs ft of torque at 2400 rpm.

Those outputs were broadly similar to the US-spec 4.2 but gave notably better fuel economy. America had briefly embraced diesel following the 1979 oil embargo and Mercedes had introduced diesel versions of both W123 and W126 models, which had proven popular. In 1981, a BL spokesman told Car magazine they planned to introduce it into the US market for the 1983 model year.

However as fuel consumption concerns abated, the diesel XJ, despite having been largely proven was shelved; Jim Randle telling Motor’s Jeremy Sinek in 1983, “should the market require it in future, we could introduce it quite rapidly”. Another missed opportunity perhaps, since such an engine might have opened Jaguar to more of the European market.

Randle expanded a little more on this matter when we spoke in 2016. “We looked at diesel engines in the early ‘80s, using VM. It was built like an Aston Martin engine, where you have a tunnel through the crankcase, and each of the main bearings sits in a circular cup, as it were. It was interesting, turbocharged, but not a performer. It had the potential for finding some extra customers, but in the end, I think, sales and marketing weren’t keen”.

When I put it to him that perhaps a diesel didn’t really fit with Jaguar’s NVH ethos at the time, he replied; “No, it was difficult – mostly airborne [noise] though. We put extra sealing on the bulkheads, and things like that. But no, it didn’t immediately cause you to want to buy one”.

Upon reflection, it does appear that perhaps instead of viewing Browns Lane as a thorny irritant to be subdued, BL might have been better served by having employed Jaguar as the primary power-unit technology-centre for the group. Certainly their V12 engine had the potential to be sliced and diced in a number of ways which could potentially have been highly beneficial to the business as a whole and to Jaguar as a profit centre within the organisation. Another case of the BL charter?

24 thoughts on “Saving Grace – Part Six”

Jaguar’s diesel projects were rather confusing ranging from the 3.6 VM Motori turbodiesel (likely the same used in the AMC Eagle), Project Iceberg’s dieselization of the Rover V8 (giving Jaguar the jitters) and apparently the Jaguar AJ6 engine (which was said to be built with dieselization in mind).

The first two were putting out around 150 hp (though some claim the Project Iceberg turbodiesel was only good for 125 hp not 150 hp), which would have potentially served as benchmarks for a theoretical AJ6 turbodiesel.

If Mercedes-Benz managed to build both 60-degree V6s and 90-degree V8s on the same production line, surely Jaguar was capable of performing a similar feat with a 90-degree V8 being built alongside 60-degree V6s/V12s (instead of the abortive 60-degree V8) with the former sharing much of the latter’s architecture?

Speaking of the Jaguar V12 aside from forming the basis of smaller V8 and V6 engines, in retrospect what else could have been done to improve it beyond the unrealised DOHC versions that were said to not have been an improvement over the existing V12?

NVH problems of a sixty degree V8 could have been solved by the same measures taken to tame a ninety degree V6: stepped crankpins. These would even have allowed the choice between an ‘American’ uneven 540/180 firing order or an ‘Italian’ 360/360 firing order. The eternal problem of all sixty degree engines would have remained, lack of space between cylinder banks.

I remember seeing Jaguars (can’t memorize whether they were SII or SIII) with Steyr experimental diesel engines. Six cylinder inline, cast iron cylinders with tunnel type crankshaft carriers (very unusual, like the VM engines) in one piece and a separate, vertically split aluminium crankcase with integral sump totally separate from the cylinder unit with a two fingers wide rubber seal running between the two units around the engine just below the cylinder head. The engines were direct injection pump jet types without turbo with very rough running characteristics but impressive torque.

“If Mercedes-Benz managed to build both 60-degree V6s and 90-degree V8s on the same production line,”

The Mercedes V6s introduced in the late 90s were ninety degrees so they could be built on the V8 production line. Their current V6s are 60 degrees. I’m not sure if they are built on the same line or not.

A modern engine machining factory has more flexibility, but back in the day, the transfer machines they were using had a fixed angle for the cylinder banks that could not be altered. The cylinder honing equipment, drills, milling machines, cutters, broaches… etc.. were all at a fixed angle.

Is it known what the displacement of the experimental Steyr diesel engines were and whether they were used in marine or military applications?

Angel Martin

So engine machining factories of the period did not have the same flexibility as today? Seem to recall an article or few saying the M276 60-degree and M278 90-degree V8 engines were built on the same production line along with sharing a number of features with each other.

The diesel engined Jaguars I mentioned were Steyr’s project, not Jaguar’s. Steyr chose the XJ because they wanted to show off their new engine concept in a car known for its smooth running engines.
*IIRC* the engine had a bit over three litres and around 150 or 160 hp and was one of the first applications of pump jet direct injection in car engines long before Fiat brought the first direct injection Croma. The weird two piece block design was chosen for its noise suppression characteristics.

The only references on Steyr’s inline-6 diesels online (or at least their modern day versions) seem to displace around 3.2-litres. Given the direct-injected Croma diesel appeared in 1986, would it be accurate to say Steyr’s project was around the mid-1970s to early-1980s?

I don’t remember the precise year, but it must have been around 1980. I just happened to visit Jaguar Salzburg where there was (no relation to my visit there) a press information day on these Steyr-engined Jaguars. The journalists invariably compared the diesel to the V12 and commented accordingly, which was a bit unfair because the engine actually was astonishingly cultivated, particularly taking into account it was an early pump jet design without much electronics.

Dave: Comparing just about any contemporary internal combustion engine with Mundy and Hassan’s V12 was more than a little unfair, least of all a diesel unit. The timelines are interesting however, given that at the time, Stan Paskin was overseeing the VM Motori installation into the XJ at Browns Lane. But then, the motor industry is a contained and somewhat incestuous micro-universe, so it’s perhaps possible the chaps at Steyr got wind of this and made something of a counter-pitch.

Bob: From my understanding, Harry Mundy (who became Jaguar’s Director of powertrain Engineering as well as co-architect of the V12) schemed AJ6 with one eye at Mercedes’ well-regarded contemporary diesel engines, telling journalist Ronald Barker in 1988 that his rationale was that should they require a diesel AJ6 variant, it would be more straightforward to duplicate ground already broken at Sindelfingen. However, to the best of my knowledge, no DERV AJ6 was built. However, it is said to have dictated AJ6’s basic architecture to the degree that it was a physically larger block than it might otherwise have been. However, when I put it to Jim Randle as to whether AJ6 had been conceived as a modular unit (four/five cylinder), as some journalists (step forward Mr. Cropley) suggested, he made it clear that no such plans existed.

Just for the sake of clarity, the abortive V8 was a 60 degree unit, derived from the V12’s inclined angle. It was abandoned owing to seemingly intractable NVH issues. However, I spoke to an engineer who spent his formative years working with Ralph Smith in Whitley at Jaguar’s Advanced Engineering skunkworks during the late 1980s, who told me he solved the rough-running issue with this unit. This might perhaps suggest that the issues as outlined could have been a matter of dogma as much as anything. However, given that both Bob Knight and Harry Mundy are no longer with us, I am reluctant to endorse this view. You will find more on the subject of this power unit in our interview with Jim Randle in the archive.

The V12 deserves an article in itself (which will happen in the fullness of time), as its creation (like most Jaguar projects) was somewhat convoluted, so I will refrain from commenting further on that matter for the present.

So Harry Mundy was looking to the 5-cylinder Mercedes-Benz OM617 diesel as inspiration for a potential dieselized AJ6 engine?

Thought it was the 6-cylinder Mercedes-Benz OM603 however the latter appeared about 2 years after the AJ6 engine.

Have read about Jaguar’s abortive 60-degree V8 engine project, though find it difficult to believe Jaguar seriously considered it instead of looking at a 90-degree V8.

Jaguar did after all look at 1.8-2.5 Coventry Climax CFF/CFA V8 for their Junior XJ project (not sure whether there was room for further enlargement) and already had the Daimler V8, which despite its apparent limitations deserved a better fate. Have heard of murmurs about Jaguar looking at other V8 projects during the 1950s-1960s though nothing viable as a production car engine.

I always thought that the opportunity missed by Jaguar on engines was the late 1970’s redesign of the XK6 with a new, lighter block and 4 valve per cylinder aluminum head.

The idea was a lighter cast iron block based on a new casting with slightly reduced capacity and bore size for better cooling and a 4 valve head for ~240 hp (also 4 valves gives approx 10 percent better fuel consumption).

The block could have been machined and built on existing machinery. And used the BL experience (positive and negative) from the Dolomite Sprint engine.

Ironically, that would have been a low cost, low risk, high return engine program of the type which has always been shunned by Jaguar. Their pattern is to swing for the fences with high cost, high risk powertrain designs. (eg V12, AJ8, all electric)

The experimental alloy XK unit was a 3.8 litre, which was pretty much the optimum swept volume for that power unit. Nobody had much time for the 4.2 But either way, owing to its antiquity, it remained an enormous lump of thing.

The issue of the XK redesign was addressed by Jim Randle in a 1983 interview in Motor magazine. In this he outlined that the primary drawback with the XK unit was not only its age in conceptual terms, but the age of its tooling. He pointed out that the costs involved in producing it with an alloy block (which had been envisaged) and Harry Mundy’s 24 valve cylinder head was such that they might as well design a new engine from scratch, avoiding legacy issues which the XK unit was saddled with and obtaining the benefits of a lighter, more adaptable engine.

One of these aspects in AJ6’s favour was, that there was considerable scope to, as Mr. Randle put it, ‘tighten economies if necessary’ – one of the potential developments being something akin to what BMW were doing at the time with their ETA series of engines – the thinking of which he described as being in his view quite sound.

Unfortunately, I’m separated from my archive at present, so am unable to furnish direct quotes, so this thumbnail sketch (so to speak) will have to suffice for the present time.

“He pointed out that the costs involved in producing it with an alloy block (which had been envisaged) and Harry Mundy’s 24 valve cylinder head was such that they might as well design a new engine from scratch,”

This is my point about Jaguar. Always the high risk design. In this case a completely new block with a change to aluminum and a completely new rotating assembly, as well as a new head. As well as a completely new assembly line, new castings, entirely new machines, new production process.

Much more potential for problems. Many more potential points of failure. Especially risky for a company like Jaguar with prior reputation for iffy quality, reliability and durability.

Compare to: an updated XK engine where they use an evolution of the existing engine rotating assembly, a new thin wall casting of the existing block in cast iron (so none of the risks of aluminum blocks) and a new cylinder head. Replace the worn machines on an assembly line that already exists, that works and is reliable ,and that the employees now how to build.

It seems to me that a small company like Jaguar would want to be risk averse when the upside isn’t that big and the downside is really huge.

I acknowledge your point Angel but what I will say is that AJ6 proved to be a very robust engine in service, in addition to being quite an efficient one. It was probably the closest Jaguar came to producing a bulletproof engine and certainly proved the least of XJ40’s issues, which were it seems mostly electronic in nature. Additionally, I’m not certain that a revised XK as you envisage would have given them a smaller capacity unit. Although it was rather underpowered, the 2.9 AJ6 opened Jaguar to a market the larger capacity unit would never have unlocked – especially where the latter would have been prohibitively taxed.

From reading about the proposed 2.6-3.0-litre all-alloy short-stroke XK6 engines that was envisioned to put out 185 hp (Net) in 3-litre form, was under the impression based on the 2.6-litre versions enlargement to the (albeit largely unrelated / notorious) 2.6-litre would have meant a theoretical enlargement from a 3-litre to a 3.2-litre potentially putting out around 197 hp (Net)?

Additionally how to the proposed 2.6-3.0-litre all-alloy short-stroke XK6 engines differ from the experimental 3.8-litre alloy XK6 unit or were both projects linked?

Yes, the AJ6/AJ16 was probably Jaguar’s most robust engine (certainly at launch). But they got lucky. Compare to the AJ8.

My point is the risks of doing too much new stuff all at once. Look at the XJ40. There were so many new components and manufacturing processes on that car – no wonder they had launch problems !

If the XJ40 was launched with only the new body, the new paint shop, new abs and new rear suspension they would have been much better off.

As it was they also had a new engine control, new high pressure hydraulics, new digital dash, new climate control, all new electrical system, new self levelling rear suspension…. It they had deferred or skipped all of that and used updates of existing components they would have had a much better launch. Those things could have been added incrementally to mid-cycle updates.

Ironically, a lot of that stuff had disappeared by late XJ40 production anyway !

On the smaller AJ6, all AJ6s used a 91mm bore and different stroke lengths, so an updated block casting XK presumably could have done the same.

Angel: You are not alone in taking that view – in fact, another former Jaguar insider I spoke to held broadly similar opinions. On one hand I can accept the contention, and when I put it to Mr Randle that perhaps a less technically dense car might have been a more expedient proposition, he was quite insistent that all of the ‘innovations’ within XJ40 were a direct response to the known and much-criticised problems with the earlier cars and were conceived to ensure durability. In addition, XJ40 was created in this manner in order to jump a 20-year technological gap, owing to the stagnation which occurred under BL. Whether Jaguar was in a position to build such a car is a good question. I think we can safely say from a distance of years that they were not.

On the other hand I maintain that there is something rather laudable in the attempt to reach for excellence when something less would probably have sufficed. Where would we be without this approach? Probably where we are now, I might suggest. So yes, perhaps Jim Randle and Jaguar took an over-ambitious path, but as someone who appreciates elegant engineering, I’m rather glad they did – in the same way as I applaud the adoption of a V12 when yet another V8 in a world drowning in the things would have been enough.

It isn’t as though the outcomes would have been vastly different anyway. If XJ40 had been technically a warmed over Series III, it would still have been viewed entirely within its predecessor’s shadow, Ford would still have taken over in ’89, as they would not have been denied. The cars that followed would still have been watered down and the styling retro-focused. If anything, the ’40 would probably have been even more derided in retrospect – at least those who understand it can appreciate the fact that it was a rather intelligent piece of engineering, if lacking the impossible grace of Series III – a body design which has never been surpassed, by Jaguar or anyone else.

I’m not expecting to convince anyone on this – I have to admit to a wholly irrational (and unapologetic) bias towards XJ40 and its creators.

Bob: I don’t know if the 3.0 litre alloy block XK envisioned for the XJ4 programme was related to the 3.8 litre 24-valve unit developed during the early ’70s. Very little is documented about either engine and sadly, most of the people who were directly involved are no longer above ground. Part of the reason for this of course is that most of them came to nothing owing to a chronic lack of funds. BL was obsessively focussed on the volume car division and everyone else could essentially go whistle.

“On the other hand I maintain that there is something rather laudable in the attempt to reach for excellence when something less would probably have sufficed. ”

Eoin. I guess it is just a difference in philosophy. Bad launch quality is never excellence in my view. Toyota limits the number of new features and new production processes in any model launch because they know how dangerous too much new stuff is to quality.

I’m actually a fan of the XJ40, even the styling. But I much prefer the later cars when the failure prone crap had been removed.

Actually, Eóin, with your insights into the workings of Jaguar, and the toxic BL political environment within which it operated, you’ve gone a long way towards convincing me that there was really something heroic about the XJ40, even if its execution was tragically flawed. It’s easy for companies like Toyota that replace models with metronomic regularity to pursue a cautious and incremental approach to the introduction of new technologies but, as you point out, Jaguar was trying to make up for almost two decades of elegant stagnation. Also, one shouldn’t forget that the XJ40 was good enough to be evolved into the X300 and X308, giving it an impressive lifespan of 17 years. Without the xJ40, it’s doubtful that there would have been anything that Ford would have considered worth buying*, so Jaguar might no longer exist.

What would it have hurt if the launch had been limited to:
-body structure
-paint process
-anti-lock brakes
-rear suspension

and the rest introduced at a mid-cycle refresh in 1990 when they had more opportunity to test them?
-revised engine electronic control
-high pressure hydraulics
-electrical wiring system
-new climate control
-digital electronic dash
-self-levelling rear suspension

After two decades, what is another 3 years to get it right?

Jaguar spent the 1980’s trying to rebuild their shattered quality reputation, then they destroyed it again with the XJ40. And the main culprits were items like the digital dash and self levelling suspension which they deleted in later models anyway. Brilliant !

If I was more charitable I would not point out that Jaguar wasted budget and engineering resources on nonsense like a digital dash when they KNEW that the USA had a supplemental restraint mandate coming into force. And, instead of having airbags in place when competitors did, the XJ40 had to make do with mouse belts.

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